You are correct. Using Multicast for music collaboration would add a significant amount of delay for most of the people in the session. In most cases the amount of introduced delay would be well beyond the acceptable ranges for synchronized playing.

Multicast, however, could be great for broadcasting jam sessions to your friends, fans, or anyone who wants to hear what you are doing in real-time.

To answer your question above. it is possible to do this. We have actually had many people ask for it. It would be really great to allow your friends and fans to listen-in on your jam sessions without having to have them actually join in. Let's just say that this is on the roadmap.